Self-referenced multiplex CARS imaging with picosecond pulse generated supercontinuum by using second and third order nonlinearities

Abstract

Among the various imaging methods, the multiplex Coherent Anti-Stokes Raman Scattering (M-CARS) technique has received a special attention from the researchers. Indeed, its capability to provide quickly, simultaneous information about various molecular vibrations is of high interest. Over the past years M-CARS microscopy has typically relied on using a supercontinuum, which is generated in photonics crystals fibers (PCFs) with the cubic nonlinearity. This technique requires an additional optical delay line to temporally synchronize the pump and the Stokes pulses [1] . Significant simplification could be introduced by exploiting other nonlinear processes that allows to generate ultra-broadband spectrum without temporal desynchronization between the pump and the supercontinuum pulses. In this work we demonstrate three direct, self-referenced M-CARS systems that do not require any delay line, by using different nonlinear components such as a PPLN crystal (χ (2) and χ (3) ); a YAG:Nd crystal (χ (3) ) and a GRIN multimode fiber (χ (3) ) under the Kerr beam self-cleaning regime [2] .